Sphex \Sphex\, n.[NL., fr. Gr. ???, ???, a wasp.]

(Zo["o]l.) Any one of numerous species of sand wasps of the genus Sphex and allied genera. These wasps have the abdomen attached to the thorax by a slender pedicel. See Illust. of Sand wasp, under Sand.

Sphex fly (Zo["o]l.), any one of numerous species of small dipterous flies of the genus Conops and allied genera. The form of the body is similar to that of a sphex.

Source: Webster's Revised Unabridged Dictionary (1913)